Smoking articles such as cigarettes are conventionally made by wrapping a column of tobacco in a white wrapping paper. At one end, the smoking article usually includes a filter through which the article is smoked. Filters are attached to smoking articles using a tipping paper which is glued to the white wrapping paper. The wrapping papers and tipping papers used to construct smoking articles are typically made from flax or other cellulosic fiber and contain a filler, such as calcium carbonate.
Besides being used to hold the cigarette together, cigarette wrapping papers and tipping papers also contribute to and control many physical properties and characteristics of the cigarette. For instance, cigarette wrapping paper affects the rate at which the cigarette burns, the number of puffs per cigarette and the total tar delivery per puff. Another property of the cigarette that is affected by the wrapper is the appearance and the characteristics of the ash that is formed as the cigarette burns. Cigarette paper can even be used to limit the amount of smoke that emanates from the lit end of a cigarette when it is left burning and to reduce the tendency of a cigarette to ignite adjacent surfaces.
In the past, wrapping paper opacity was determined primarily as a function of the amount of filler incorporated into the papers. In general, opacity levels are increased as the amount of filler added to the paper is increased. Unfortunately, however, increasing filler levels to increase opacity can adversely affect other characteristics of the paper. For example, increasing filler levels can decrease the strength of the paper. Altering filler levels can also affect the permeability of the paper which may in turn affect the burn properties of the paper. As such, there is increasing pressure within the industry to keep filler levels in cigarette paper within preset ranges, severely restricting viable methods for increasing paper opacity.
Currently, focus has also been placed upon decreasing the basis weight of wrapping papers in order to decrease the amount of material needed to produce the papers. By reducing the basis weight of wrapping papers, however, two problems can result. First, by reducing the basis weight, the opacity of the wrapping paper is simultaneously decreased causing the paper to aesthetically decline in appearance by unmasking the cigarette's contents. Decreasing the basis weight of the wrapping papers also can cause a decrease in the tensile strength of the paper.
Due to the above limitations, it has been extremely difficult to create a wrapping paper with a decreased basis weight while maintaining an opacity and tensile strength level that is commercially acceptable.
Thus, a need exists for a wrapping paper for smoking articles that has a decreased basis weight while at the same time maintaining an opacity of at least 70% and a tensile strength above minimum commercial requirements. Also, a need exists for a method of producing such wrappers. A need also exists for a method of reducing basis weight without adversely interfering with other physical properties of the paper.